COPD overdiagnosed in 62% of study cases

Takeaway

• The Burden of Obstructive Lung Disease (BOLD) study from 20 countries finds that around 62% of COPD cases are overdiagnosed (as defined by postbronchodilator unobstructed spirometry).

Why this matters

• A previous study by BOLD, published in 2013, found the opposite problem: 81% of cases were undiagnosed.
• Now, overdiagnosis is the problem, as is overtreatment, which exposes nonobstructed patients to possible adverse events.

Study design

• Population-based cohort (n=16,177) in 20 countries by the BOLD study.
• Funding: Wellcome Trust; Boehringer Ingelheim China; Merck & Co., Inc., Kenilworth, NJ, USA; others.

Key results

• 5.7% of cohort reported a previous medical diagnosis of COPD, but:
  • 61.9% of them were overdiagnosed (unobstructed postbronchodilator spirometry: FEV₁/FVC>lower limit of normal).
• Using the more widely used fixed-ratio criterion (unobstructed postbronchodilator spirometry: FEV₁/FVC<0.7), 55.3% were overdiagnosed.
• Overdiagnosis occurred more frequently in high-income countries (4.9% prevalence) vs 1.9% prevalence in low- to middle-income countries.
• Overdiagnosis occurred more frequently among these groups (all Ps<.001 in multivariate analysis):
  • Women: OR, 1.61.
  • Higher education: OR, 1.06.
  • Former smokers: OR, 1.67.
  • Current smokers: OR, 1.54.
  • Those with wheeze: OR, 2.52.
  • Those with cough: OR, 1.64.
  • Those with phlegm: OR, 1.52.
  • Co-occurring asthma: OR, 4.04.
  • Co-occurring heart disease: OR, 1.71.
• Among false-positive subjects, 45.7% reported currently using respiratory medicine.

Limitations

• Observational design.